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38 results about "Triangular element" patented technology

Coherent signal arrival direction estimation method and device based on deep convolutional network

The invention provides a coherent signal arrival direction estimation method and device based on a deep convolutional network, and belongs to the field of array signal processing. The method comprises the following steps: receiving a to-be-detected signal containing a coherent signal by using a uniform linear array antenna to obtain an array receiving data matrix and extract a covariance matrix; forming an input feature vector by right upper triangular elements divided from a diagonal line in the covariance matrix, inputting the input feature vector into a covariance estimation model formed by a deep convolutional network, obtaining an estimation value of the right upper triangular elements under an ideal incoherent condition, and reconstructing the estimation value to obtain a covariance matrix estimation value; and performing characteristic decomposition on the covariance matrix estimation value, and generating a spatial spectrum by using a MUSIC algorithm to obtain an estimation result of the signal arrival direction. According to the method, the noise-containing mixed signal covariance matrix is mapped into the ideal incoherent noise-free signal covariance matrix through a physical constraint supervised learning framework, so that the estimation precision and robustness of the MUSIC algorithm in a coherent scene are improved.
Owner:TSINGHUA UNIVERSITY

Cavity target infrared characteristic calculation ray tracing method

The invention provides a cavity target infrared characteristic calculation ray tracing method, and belongs to the technical field of infrared tracing. The method comprises the following steps: importing a CFD data source; a cuboid space grid is generated, and CFD data space distribution is interpolated and reconstructed; a target material and temperature parameters are set; determining the position of a detector and forming a detection situation relationship; gridding a detection space in the transverse direction and the longitudinal direction at the position of the cavity object to form a field pixel space; constructing a reverse ray vector direction, and counting self reflection and reflection radiation of each triangular infinitesimal according to a recursive iteration mode; reconstructing a broadband spectral reflection coefficient according to the narrowband BRDF model and the broadband spectral emissivity; and determining the reflection direction of the infrared rays based on a bidirectional reflection distribution model to realize ray tracing. According to the invention, the control of any ray tracing depth can be realized, the intersection judgment process is greatly simplified, and the problem of high-efficiency and high-precision calculation of the cavity and the low-emission material is effectively solved.
Owner:THE 54TH RESEARCH INSTITUTE OF CHINA ELECTRONICS TECHNOLOGY GROUP CORPORATION

Aircraft structure finite element calculation result data noise reduction method

The invention belongs to the technical field of airplane structure strength digital twinborn model construction, and particularly relates to an airplane structure finite element calculation result data noise reduction method, which comprises the following steps: step 1, preliminarily identifying deformity units including triangular units and high slenderness ratio units; identifying the triangular units based on the continuity of the node numbers; identifying a high slenderness ratio unit based on the side length; 2, defining a stress concentration area, and removing units in the stress concentration area from the deformed units; defining a stress concentration region including a hole edge, a fillet, a boundary constraint position and a region where a concentrated load applying position is located; 3, calculating the gradient of the deformity units, and removing units in a real physical gradient field from the deformity units; step 4, carrying out noise reduction processing on the calculated value of the malformation unit; and smoothing the calculated value of the malformed unit, or removing the calculated value of the malformed unit.
Owner:CHINA AIRPLANT STRENGTH RES INST

Cylindrical surface or similar cylindrical surface homeomorphic parameterization method for grid redivision

The invention discloses a cylindrical surface or similar cylindrical surface homeomorphic parameterization method for grid redivision, which comprises the following steps: carrying out feature recognition on a geometric surface to be parameterized, and if the geometric surface has the features of the cylindrical surface, defining the inner and outer boundaries of the complete cylindrical surface; performing parameterization processing of conformal mapping on all triangular units of the grid according to the new boundary; and checking and correcting the quality of the parameter plane target grid. The defect that the cylindrical surface cannot be directly unfolded to a two-dimensional parameter plane under the condition that the cylindrical surface is not sheared off is overcome, the characteristics of the cylindrical surface can be kept when the method is applied to grid re-division, and therefore reasonable deformation of grids can be achieved, the defects of large grid distortion, grid self-intersection and the like are overcome, and the user-friendly purpose is finally achieved.
Owner:SHANGHAI GEYU SOFTWARE CO LTD

Numerical simulation method and system for whole process of ore rock fracture based on FDEM impact load

The invention relates to the technical field of numerical simulation of rock dynamics, in particular to a numerical simulation method and system for the whole process of ore rock fracture based on FDEM impact loads.The method comprises the steps that a continuous medium structure is discretized into a finite element network composed of triangular units through FDEM, and an ore rock impact test model is constructed; setting material parameters and impact speed boundary conditions according to the ore rock impact test model; a normal contact force calculation model and a tangential contact force calculation model are established according to material parameters and impact speed boundary conditions, and coordinates and speed updating results of triangular unit nodes are obtained in combination with the Newton second law and the calculation models; and performing visual analysis based on the coordinate and speed updating result, and outputting crack propagation, stress field and energy evolution results under the impact load. The method can accurately simulate the crack propagation, the fracture mode and the energy evolution law of the ore rock under the impact load, quantitatively researches the crushing characteristics and the energy evolution law of the ore rock, and provides a calculation method for the research of the crushing mechanism of the ore rock.
Owner:KUNMING UNIV OF SCI & TECH

Antenna grid installation method for antenna layout design

The invention relates to an antenna grid installation method for antenna layout design, and belongs to the technical field of electromagnetic compatibility and antennae, and the method comprises the steps: importing a grid model file of a large-size platform and an antenna, and reading a grid model to obtain a point coordinate list and a triangular unit list of the platform and the antenna; reading a starting point coordinate, a termination point coordinate, a voltage amplitude and a phase of an excitation voltage source of the antenna; establishing an antenna initial coordinate system, setting the main radiation direction of the antenna to establish a surface local coordinate system on the surface of the platform, and performing point matching on the model; and mounting the antenna grid model and the excitation source on the surface of the platform. According to the method, direct processing of complex grids is supported, limitation of traditional CAD modeling is broken through, subdivided discrete grids can be directly operated, and model reconstruction is avoided; through normal offset control and local coordinate system mapping, the normal function of the installed antenna is ensured, and the installation efficiency can be significantly improved on the premise of maintaining high-precision electromagnetic characteristics.
Owner:CHINA SHIP DEV & DESIGN CENT +1

Three-dimensional discrete element flexible undrained loading method based on dynamic geometry

The invention belongs to the technical field of three-dimensional discrete element loading, and aims to solve the technical problems that a hexagonal unit is mostly adopted in the current discrete element three-axis undrained loading and volume monitoring process, adjacent particle pointers need to be repeatedly read through id numbers, a large amount of vector operation is carried out, and the computing power is wasted. The invention provides a three-dimensional discrete element flexible undrained loading method based on dynamic geometry, and the method comprises the steps: simplifying a hexagonal basic unit in a conventional flexible film loading process into a simpler triangular unit through introducing a geometry unit; and in combination with the specific area and normal vector extraction advantages of the geometer poly unit, the load application and volume dynamic monitoring process in the non-drainage loading process of the flexible film is effectively simplified, and the related research of the discrete element three-dimensional flexible film is promoted.
Owner:XI'AN UNIVERSITY OF ARCHITECTURE AND TECHNOLOGY +2

A free-form surface machining track generation method based on conformal mapping

ActiveCN119620681Breduce distortionNumerical controlTriangular elementMachining
The present application relates to the technical field of machining, in particular to a free curved surface machining track generation method based on conformal mapping, which first selects an input three-dimensional triangular mesh curved surface; then uses a boundary-first unfolding algorithm to unfold it into a two-dimensional parameter domain triangular mesh plane, so that the obtained two-dimensional parameter domain triangular mesh plane is rectangular, and the deformation generated by the mapping is minimal; the next step is to deform the shape of the two-dimensional parameter domain triangular mesh plane to the size of the design area; after a designer plans a two-dimensional machining track on the design area, i.e. the deformed two-dimensional parameter domain triangular mesh plane, the machining track is discretized into a plurality of machining track points, and the barycentric coordinates of the machining track points in the corresponding triangular elements of the two-dimensional parameter domain triangular mesh plane are calculated, and finally the machining track points are inversely mapped onto the input triangular mesh curved surface, so that the input three-dimensional machining track is obtained. The present application solves the shortcomings of the prior art and can adaptively generate a corresponding spatial machining track on a three-dimensional curved surface.
Owner:GUILIN UNIV OF ELECTRONIC TECH

Stealth coating damage area three-dimensional reconstruction method based on microwave thermal imaging

The invention relates to a microwave thermal imaging-based stealth coating damage area three-dimensional reconstruction method, which belongs to the technical field of measurement, solves the problem of insufficient reconstruction accuracy of stealth coating damage in the prior art, and comprises the following steps: S1, carrying out microwave thermal imaging treatment on a stealth coating with damage to obtain an infrared temperature cloud picture of the surface of the stealth coating; s2, processing to obtain a to-be-reconstructed invisible coating damage area; s3, dividing a to-be-reconstructed invisible coating damage area into triangular surface element grids of a plurality of planes; s4, the center of each triangular surface element grid obtained through division is calculated, the center temperature of each triangular surface element grid is obtained, and the generalized reflectivity of the center of each triangular surface element grid is calculated; s5, calculating the depth of the center of each triangular surface element grid; s6, constructing a triangular body element by combining the depth of the center of each triangular surface element grid; and S7, combining all the triangular voxels to obtain the damage area of the three-dimensional reconstructed stealth coating.
Owner:BEIHANG UNIV +1

A method for generating signed distance fields of characteristic polyhedrons based on surface mesh features of objects

The technical solution of the present invention provides a method for generating a three-dimensional signed distance field based on a characteristic polyhedron of an object's surface mesh. The method comprises constructing a characteristic polyhedron from surface features derived from triangular elements in the object's STL surface mesh file; and generating a narrowband signed distance field from the characteristic polyhedron. The method provided by the present invention is not limited by the geometric complexity of the object or the resolution of the domain. The method can construct the characteristic polyhedron and its boundary volume for generating the signed distance field from the surface features of the triangular elements in the STL surface mesh file, directly using the modeling file, shortening the process. The characteristic polyhedron and its boundary volume data are processed by a specific algorithm to achieve accurate generation of the narrowband signed distance field in a method that efficiently saves computing resources, optimizes storage space and generation time, and reduces computational difficulty.
Owner:SHANGHAI SUOCHEN INFORMATION TECHNOLOGY CO LTD

A global-local divergence based multivariate time series unsupervised dimensionality reduction method

ActiveCN116401528BFeature setAlgorithm
The application discloses a kind of multivariate time series unsupervised dimension reduction method based on global-local divergence, it includes the following steps: S1, the covariance matrix of multivariate time series is calculated, the upper triangular element of covariance matrix is extracted, it is combined as feature sequence, obtain the feature set Fea of multivariate time series={f i |i=1,2,…,n};S2, using k near neighbor and Euclid Distance (Euclid Distance, ED) measure is established neighborhood set N k (f i )={f j |j=1,2,…,k};S3, after finding the neighborhood of each sample point, the neighborhood center sequence m i Of each feature sequence f i In feature set is calculated;S4, with the neighborhood variance of sample point after projection, local divergence is characterized.First, the variance of each sample point neighborhood set after projection is calculated, then the sum of the accumulation of these variances is obtained, to obtain local divergence;S5, according to the field center point obtained in step S3, the variance of field center point is calculated to obtain global variance.Finally, the low-dimensional projection sequence obtained by the experimental result shows that the method can represent original MTS, and obvious dimension reduction is realized.
Owner:AIR FORCE UNIV PLA

Electromagnetic surface wave transmission method based on wave-absorbing coating damage three-dimensional reconstruction

The invention provides an electromagnetic surface wave transmission method based on wave-absorbing coating damage three-dimensional reconstruction, and belongs to the technical field of measurement, and the method comprises the following steps: carrying out microwave heating treatment on a damaged wave-absorbing coating sample, and carrying out computer treatment to obtain a surface temperature cloud picture of the sample; extracting an area of which the surface temperature of the wave-absorbing coating is higher than the test environment temperature from the surface temperature cloud picture; performing triangular surface grid division on the extracted region, and combining all triangular volume elements to realize three-dimensional reconstruction of the damaged region of the wave-absorbing coating; constructing a surface wave propagation method based on a dispersion equation; a dispersion equation is utilized to analyze transmission of surface waves in the three-dimensional reconstruction model of the damaged area of the wave-absorbing coating, the influence of the thickness of a triangular voxel and electromagnetic parameters of a combined model of the triangular voxel on a surface wave attenuation constant is discussed, and a surface wave attenuation constant model based on three-dimensional reconstruction of the damaged area of the wave-absorbing coating is constructed. The method provides a theoretical basis for damage evaluation of the wave-absorbing coating of the aircraft.
Owner:BEIHANG UNIV

A lightweight deep neural network array direction finding method based on data deduplication

This invention discloses a lightweight deep neural network array direction finding method based on data redundancy removal, which solves the problem that the traditional RDNN direction finding method has a large number of deep neural network nodes and cannot achieve network lightweighting. The method performs redundancy removal operation on the upper triangular elements of the covariance matrix, simplifies the number of subsequent hidden layer nodes, reduces the computational complexity of the model, and ensures that the direction finding accuracy of the model is not lost, thus realizing high-precision direction finding of lightweight deep neural networks.
Owner:NORTHWESTERN POLYTECHNICAL UNIV

A cylindrical or quasi-cylindrical homeomorphism parameterization method for mesh re-meshing

The application discloses a cylindrical surface or cylindrical surface-like homeomorphism parameterization method for mesh redivision, and comprises the following steps: feature recognition is performed on a geometric surface to be parameterized; if the geometric surface has the feature of a cylindrical surface, the inner and outer boundaries of a complete cylindrical surface are defined; parameterization processing of conformal mapping of all triangular elements of the mesh is performed according to the new boundaries; and the quality of the target mesh of the parameter plane is checked and corrected. The application makes up for the deficiency that the cylindrical surface cannot be directly unfolded to a two-dimensional parameter plane without being cut, can keep the feature of the cylindrical surface when applied to mesh redivision, can achieve reasonable deformation of the mesh, and can avoid the disadvantages of large mesh distortion and mesh self-intersection, and finally achieves the purpose of user friendliness.
Owner:SHANGHAI GEYU SOFTWARE CO LTD

Two-dimensional interferometer direction finding method based on multi-frequency sparse area array

The invention discloses a two-dimensional interferometer direction finding method based on a multi-frequency sparse area array. The method mainly solves the problems that in the prior art, the array arrangement space size is limited, and the two-dimensional DOA estimation precision is poor in a low signal-to-noise ratio scene. Comprising the following steps: 1) constructing a sparse plane physical array; 2) carrying out channelization processing on the broadband signal received by the antenna; 3) acquiring a vector signal model of the mapped channel by taking the center frequency of the Lth channel signal as a reference; 4) selecting effective channel data from L-1 channels, mapping all the center frequencies of the effective channel data to the center frequency of the Lth channel signal, and combining the signals; 5) calculating the covariance of the signal, and extracting the phase of a triangular element on the matrix; and 6) selecting a phase difference corresponding to the virtual baseline from the extracted phases, and realizing two-dimensional interferometer unambiguous direction finding by using a long and short baseline method. According to the method, two-dimensional DOA high-precision estimation can be effectively realized, and the method can be used for realizing two-dimensional direction finding of a target by a small unmanned aerial vehicle in a low-signal-to-noise-ratio environment.
Owner:XIDIAN UNIV

STL (Standard Template Library) grid region division and re-subdivision method and device based on feature preservation

The embodiment of the invention provides an STL (Standard Template Library) grid region division and re-subdivision method and device based on feature preservation. The method comprises the following steps: acquiring an initial grid container; subdividing triangular units in the initial grid container based on a longest edge bisection algorithm; the subdivided triangular units are stored in a subdivision grid container; feature boundary extraction is carried out on triangular units in the subdivided grid container in a dihedral angle threshold value judgment mode; on the basis of the feature edges of the triangular units in the subdivided grid container, performing feature curved surface division on the triangular units in the subdivided grid container through a curved surface division algorithm based on depth-first search to obtain a plurality of feature curved surfaces; and through harmonic mapping and an AFT-Delaunay method, parameterization is carried out on the characteristic curved surface, and mesh generation of the characteristic curved surface is completed. In this way, key geometric features such as sharp edges and ridges of the model can be accurately recognized, the dependence on the initial grid quality is reduced, and the generated grid quality is greatly improved.
Owner:SHENZHEN MAIXI SOFTWARE CO LTD

A method for generating a volume grid based on a cylindrical surface grid radial growth

The application relates to a method for generating a body grid based on radial growth of a cylindrical surface grid, in the field of electromagnetic engineering, and the method comprises the following steps: reading cylindrical surface grid data, including a point list P containing three-dimensional coordinates of N p points, a triangular element list E containing vertex indexes of E e triangular elements, and an element material list M; screening target elements through material matching; establishing a local coordinate system satisfying the right-hand rule and the orthogonal normalization condition of a vector, and performing coordinate transformation; performing radial mapping on the vertices of the screened elements; inversely transforming the mapped points to a world coordinate system; and generating a body grid, and converting a six-vertex triangular prism into three four-vertex tetrahedron elements by using a topological decomposition method. The electromagnetic calculation precision is improved: in electromagnetic field design calculation, the cylindrical radial grid growth technology makes the grid resolution in a strong field area multiply, and the calculation error of a resonance frequency is less than or equal to 0.3%.
Owner:DONGXIN ELECTROMAGNETIC TECH (CHENGDU) CO LTD +1

Implantation method of large deformation plastic element based on FDEM in non-rotating reference frame

ActiveCN115828652BRealize simulationPortable and very stableSustainable transportationDesign optimisation/simulationReference configurationContact force
The application discloses a method for implanting a large deformation plastic element based on FDEM in a non-rotating reference system, which comprises the following steps: obtaining a deformation rate in a rotating configuration and a rotation matrix based on the node coordinates of a triangular element; obtaining the deformation rate in a non-rotating configuration based on the deformation rate in the rotating configuration and the rotation matrix; determining an elastic trial stress, determining a material state in combination with a yield function, obtaining a true stress, and performing rotation mapping of an original reference configuration to obtain a true Cauchy stress; according to FDEM calculation, calculating contact force and force caused by cohesive force elements, and then uniformly converting the contact force and the force into node force; updating the node velocity and the position in the current time step through Newton's second law; and entering the next time step. The application introduces the calculation of a stress tensor in a non-rotating reference system, rotates the stress tensor, maps the stress tensor to the original reference system, and realizes the accurate simulation of plastic behavior in the wired-discrete element in combination with a yield function and a plastic flow rule.
Owner:INST OF ROCK & SOIL MECHANICS CHINESE ACAD OF SCI

Numerical method for continuous and discontinuous mechanical behavior of coarse aggregates

The application provides a coarse-grained aggregate mechanical behavior continuous-discontinuous numerical calculation method, including: establishing a numerical model of coarse-grained aggregate, the numerical model including a constant strain elastic triangular element and an initial thicknessless cohesive force element distributed along the boundary of the triangular element; determining the constitutive relation of the cohesive force element in the numerical model under a continuous deformation analysis framework; determining the contact relation between discrete triangular elements in the numerical model under a discontinuous deformation analysis framework; obtaining a continuous-discontinuous coupling model of the coarse-grained aggregate based on the determined constitutive relation and contact relation, inputting boundary constraint conditions and external loads into the continuous-discontinuous coupling model according to actual working conditions, and performing simulation calculation to obtain the mechanical properties and deformation failure forms of the coarse-grained aggregate under external loads. The application establishes a corresponding numerical model through digital image analysis and recognition technology, completes continuous-discontinuous coupling calculation of the mechanical behavior of coarse-grained aggregate, and takes into account solving accuracy and calculation efficiency.
Owner:WUHAN UNIV

Two-dimensional direct current electric field forward method and device, electronic equipment, medium and product

PendingCN122310848AArea networkSparse grid
This application discloses a two-dimensional DC electric field forward modeling method, apparatus, electronic device, dielectric, and product. The method includes: taking the variational problem of a two-dimensional wavenumber domain point source DC electric field as the research object; dividing the model region of the dielectric model into several triangular elements and expanding the model region with a sparse mesh; reading the conductivity and potential of the principal nodes in each triangular element, and representing the conductivity and potential with quadratic interpolation shape functions to obtain a discrete model; constructing a system of linear equations based on the discrete model and the coefficient matrix of each triangular element; solving the system of linear equations to obtain the wavenumber domain forward modeling result; and performing an inverse Fourier transform on the forward modeling result to obtain the spatial domain electric field potential. The method increases the number of nodes in the mesh during model region meshing, reduces computation time by expanding the model, and utilizes more node property information through biquadratic interpolation of conductivity and potential within the mesh, thereby improving the accuracy of the two-dimensional DC electric field forward modeling fitting.
Owner:CHINA NAT PETROLEUM CORP +1

Construction method of quasi-regular double six-interval triangular network for searching potential sliding surface of slope

This invention provides a quasi-regular double-six discontinuous triangular mesh construction method for searching potential slope sliding surfaces, comprising: iteratively generating a quasi-regular initial triangular mesh adapted to the slope model boundary; locally dividing into six meshes to generate a six-directional arrayed topological mesh; constructing a data format of six-node triangular elements and high-order discontinuities; and solving the potential slope sliding surface using a second-order cone programming model. This invention adapts to the geometric boundaries of discrete slope models and meets the special requirements of the quasi-regular double-six discontinuous triangular mesh, forming a six-directional continuous discontinuous mesh structure within any small region. Furthermore, the double-six discontinuous mesh can be further pre-defined with local partitions, reducing resource consumption of mesh elements in non-critical areas. Applied to the upper limit finite element method of limit analysis, it achieves high-precision searching of potential slope sliding surfaces through rapid solving of the second-order cone programming problem, thus reducing computational burden while maintaining search accuracy.
Owner:CENT SOUTH UNIV

A parameterization method for nonconvex domains of complex surfaces generated by edge suppression

This invention discloses a parameterization method for non-convex domains of complex surfaces generated by edge suppression. The method includes: performing edge suppression processing on an industrial part model to extract an initial 3D network of the geometric surfaces obtained after edge suppression; performing two-point constraint conformal parameterization on the triangular elements in the initial 3D network; detecting and removing self-intersections, parameterizing again, and repeating this step until no self-intersection regions exist; detecting and correcting element normal vector flips, parameterizing again, and repeating this step until no element normal vector flips exist, at which point the parameterization ends. This invention achieves non-convex domain parameterization of spatial triangular networks of complex surfaces generated by edge suppression. By fully considering the curvature characteristics of the 3D surface, it avoids the drawbacks of generating large distorted meshes, and can meet the mesh quality requirements of subsequent numerical calculations for mechanical analysis.
Owner:SHANGHAI GEYU SOFTWARE CO LTD

Electromagnetic surface wave transmission method based on three-dimensional reconstruction of damage to wave-absorbing coating

The application provides an electromagnetic surface wave transmission method based on three-dimensional reconstruction of damage of a wave-absorbing coating, and belongs to the technical field of measurement, and comprises the following steps: microwave heating treatment is performed on a wave-absorbing coating sample with damage, and a surface temperature cloud chart of the sample is obtained through computer processing; a region with a surface temperature of the wave-absorbing coating higher than a test environment temperature is extracted from the surface temperature cloud chart; the extracted region is subjected to triangular face mesh division, and all triangular elements are combined to realize three-dimensional reconstruction of the damage region of the wave-absorbing coating; a surface wave propagation method based on a dispersion equation is constructed; the transmission of surface waves in the three-dimensional reconstruction model of the damage region of the wave-absorbing coating is analyzed by using the dispersion equation, the influence of the thickness of the triangular element and the electromagnetic parameters of the combined model on a surface wave attenuation constant is discussed, and a surface wave attenuation constant model based on three-dimensional reconstruction of damage of the wave-absorbing coating is constructed. The application provides a theoretical basis for damage evaluation of a wave-absorbing coating of an aircraft.
Owner:BEIHANG UNIV

Method and device for processing three-dimensional images that allows distortions to be minimised

The present invention relates to a method and device for processing three-dimensional images that allows distortions to be minimised in a sensor measuring the direction of a signal from a source and that comprises the steps of: providing one or more measuring sensors for measuring a signal coming from a source, the sensors being associated with one or more spatial positions, wherein the measuring sensors are configured to obtain a direction of the measured signal with respect to said spatial positions; breaking down the sensor into one or more locations; generating one or more geodesic spheres in each location, wherein each geodesic sphere comprises a set of triangular elements with vertices that are almost evenly spaced apart; encoding a signal representative of the direction between the centre of the sphere and the position of the source in a set of vertices of the sphere; and generating a vector associated with each vertex, to store information about the signal intensity.
Owner:CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS (CSIC) +3

Sub-codebook composite codebook generation method and system based on regional similarity clustering

The invention provides a sub-codebook composite codebook generation method and system based on regional similarity clustering, and the method comprises the steps: obtaining a matrix training set based on a channel covariance matrix of a large-scale MIMO system; extracting an upper triangular element of each channel covariance matrix, separating a real part and an imaginary part, and constructing a high-dimensional covariance feature training set; pCA dimension reduction processing is carried out, and a K-Medoids clustering algorithm is combined with contour coefficient optimization and an optimal number of covariance mode clusters are identified; based on the sample density weight, distributing the total code word number to each cluster in the covariance mode cluster according to a proportion, and taking the total code word number as the exclusive code word number of each cluster; obtaining an exclusive sub-codebook corresponding to each cluster; and integrating the exclusive sub-codebooks of all clusters, and constructing a final composite codebook. By extracting the triangular elements on the covariance matrix and separating the real and imaginary parts, the channel covariance mode features are accurately captured, and the adaptive capacity of the codebook to complex propagation scenes with multipath reflection, shielding and the like is effectively improved.
Owner:NANTONG UNIV

A numerical calculation method and related device for simulating crack growth in two-dimensional space

This application discloses a numerical calculation method and related device for simulating two-dimensional crack propagation, relating to the field of computational mechanics. The method comprises: obtaining a cantilever beam's overall crack solution region and a crack tip region; establishing a transition region based on the overall crack region and the crack tip region; constructing a transition region basis function based on the transition region; solving the transition region, overall region, and crack tip region based on the transition region basis function, overall region basis function, and crack tip region basis function to obtain a two-dimensional crack propagation result; the overall region basis function is a finite element basis function obtained by discretizing linear quadrilateral or triangular elements; the crack tip region basis function is a B-spline basis function; and the two-dimensional crack propagation result includes an overall displacement solution, a crack tip region displacement solution, and a transition region displacement solution. This application can accurately and stably simulate the numerical value of two-dimensional crack propagation.
Owner:CHINA SPECIAL EQUIP INSPECTION & RES INST

Triangular grid pixelation method for electromagnetic scattering center extraction

The invention relates to a triangular grid pixelation method for electromagnetic scattering center extraction, and belongs to the technical field of electromagnetic compatibility and antennae. The method comprises the following steps: reading data to obtain a model view, obtaining a point list P and a triangular unit list E of a grid, appointing the point list and triangular units, and obtaining actual direction vectors of a U axis and a V axis of the model view; calculating a projection grid model of the platform grid model on the UOV surface of the model view and an area range of the projection grid model; establishing a two-dimensional rectangular grid model by taking the region range as a boundary and taking the U-axis and V-axis directions as region coordinate axes; and traversing the projection grid model, marking effective pixel points from the rectangular grid units Gij, exporting the list H, the two-dimensional rectangular grid G and the triangular cycle list S to which the two-dimensional grid belongs, and displaying an image of the two-dimensional array grid. According to the method, calculation is simplified through the pixelated grids, and resource consumption can be reduced; a two-dimensional pixel image visually displays scattering center distribution, and analysis and calculation are facilitated.
Owner:CHINA SHIP DEV & DESIGN CENT +1

3D undulation green generation system for realistic putting simulation

ActiveKR102993461B1Computational scienceTerrain
The present invention relates to a three-dimensional undulating green generation system for realistic putting simulation. The present invention comprises: an input module that sets terrain generation parameters of the green according to the difficulty or set value of the putting simulation; and a green generation module that generates a undulating surface in three-dimensional space based on the terrain generation parameters. In particular, the green generation module is characterized by generating a random field having an irregular height distribution using a spectral density function, and selectively superimposing tilting and stepping elements thereon to generate a three-dimensional green map similar to an actual field. Furthermore, the present invention provides a realistic putting physics environment by precisely tracking the altitude of the ball through natural coordinate calculations based on triangle elements and dynamically correcting the coefficient of friction according to the slope of the green.
Owner:CORETEC

System to generate ordered quadrangular meshes and a method thereof

PendingUS20260204019A1AlgorithmQuadrilateral grid
The system is designed to generate ordered quadrangular meshes for three-dimensional, non-canonical surfaces. It includes a partitioning unit that divides the input surface into quadrangular fragments. The system features a computational unit connected to the partitioning unit, which transforms each fragment into a topological square using form functions. A subdivision module, linked to the computational unit, assigns and applies different division numbers (n1, n2, n3, and n4) to each side of the square. This process results in various mesh forms, including square, rectangular, and quadrangular elements. The system further includes a mesh generation unit connected to the subdivision module, which constructs an ordered mesh composed of convex quadrangular elements. The generated mesh ensures that neighboring elements have comparable properties, and a triangular element is added if the sum of the division numbers is odd, ensuring consistency and structural integrity in the mesh.

High-precision numerical method capable of simulating ice breaking process and ice resistance of ship in ice area, program, equipment and storage medium

According to the method, a sea ice model is constructed in a three-dimensional fluid calculation domain by adopting a gravity falling method, a ship model is dispersed into triangular units, calculation of a parallel bonding model between sea ice particles, calculation of ice loads between the sea ice particles and the triangular units and calculation of fluid action on the sea ice model and the ship model are considered, and ship icebreaking process simulation is executed. According to the invention, randomly arranged discrete units are adopted to simulate a sea ice structure, mesoscopic model parameters are calibrated according to mechanical characteristics of on-site sea ice, and isotropic mechanical characteristics of the sea ice in a horizontal plane are realized; a discrete element method is adopted to simulate numerical sea ice, the discreteness of the sea ice is simulated on the microscale, and the mechanical property of the sea ice is represented by presenting the crushing characteristic of the sea ice on the macroscopic scale; the GPU parallel acceleration technology is adopted for numerical simulation, the calculation cost is greatly reduced, and high-precision numerical simulation of the working conditions of icebreaking, rotation and tail icebreaking of a hectometer-scale ship can be achieved.
Owner:HARBIN ENG UNIV